This invention relates generally to radio frequency (RF) oscillators and more particularly to tunable RF oscillators.
As is known in the art, RF oscillator have a wide range of applications. Many of these oscillators are tunable to a particular frequency within a range of frequencies. One type of tunable RF oscillator includes a varactor diode. The varactor diode is connected to a resonant circuit, or cavity, used in the oscillator. The frequency of the RF signal produced by the oscillator is a function of the resonant frequency of the resonant circuit. The varactor diode changes its reactance in response to an applied voltage. The varactor is connected to the resonant circuit. Thus, as the applied voltage changes, the reactance of the varactor changes, and resonant frequency of the resonant circuit correspondingly changes. Hence, the frequency of the RF signal produced by the RF oscillator is tunable by the applied voltage.